Merge pull request #1022 from Microsoft/defineProperty

When augmenting Array.prototype, make the functions non-enumerable by de...

src/services/syntax/syntaxList.ts

@@ -3,6 +3,7 @@
 interface Array<T> {
     data: number;
     separators?: TypeScript.ISyntaxToken[];
+    separatedListLength?: number;
 
     kind(): TypeScript.SyntaxKind;
     parent: TypeScript.ISyntaxElement;
@@ -15,10 +16,6 @@ interface Array<T> {
 }
 
 module TypeScript {
-    export function separatedListChildCount(list: ISyntaxNodeOrToken[]) {
-        return list.length + list.separators.length;
-    }
-
     export function separatedListChildAt(list: ISyntaxNodeOrToken[], index: number) {
         return index % 2 === 0 ? list[index >> 1] : list.separators[index >> 1];
     }
@@ -31,6 +28,7 @@ module TypeScript.Syntax {
     var _emptySeparators: ISyntaxToken[] = [];
 
     _emptySeparatedList.separators = _emptySeparators;
+    _emptySeparatedList.separatedListLength = 0;
 
     function assertEmptyLists() {
         // Debug.assert(_emptyList.length === 0);
@@ -38,35 +36,44 @@ module TypeScript.Syntax {
         // Debug.assert(!separators || separators.length === 0);
     }
 
-    Array.prototype.kind = function () {
+    function addArrayFunction(name: string, func: Function) {
+        if (Object.defineProperty) {
+            Object.defineProperty(Array.prototype, name, { value: func, writable: true });
+        }
+        else {
+            (<any>Array.prototype)[name] = func;
+        }
+    }
+
+    addArrayFunction("kind", function () {
         return this.separators === undefined ? SyntaxKind.List : SyntaxKind.SeparatedList;
-    }
+    });
 
-    Array.prototype.childCount = function (): number {
-        return this.separators ? separatedListChildCount(this) : this.length;
-    }
+    addArrayFunction("childCount", function (): number {
+        return this.separators ? this.separatedListLength : this.length;
+    });
 
-    Array.prototype.childAt = function (index: number): ISyntaxNodeOrToken {
+    addArrayFunction("childAt", function (index: number): ISyntaxNodeOrToken {
         if (this.separators) {
             return index % 2 === 0 ? this[index >> 1] : this.separators[index >> 1];
         }
         else {
             return this[index];
         }
-    }
+    });
 
-    Array.prototype.separatorCount = function (): number {
+    addArrayFunction("separatorCount", function (): number {
         assertEmptyLists();
         // Debug.assert(this.kind === SyntaxKind.SeparatedList);
         return this.separators.length;
-    }
+    });
 
-    Array.prototype.separatorAt = function (index: number): ISyntaxToken {
+    addArrayFunction("separatorAt", function (index: number): ISyntaxToken {
         assertEmptyLists();
         // Debug.assert(this.kind === SyntaxKind.SeparatedList);
         // Debug.assert(index >= 0 && index < this.separators.length);
         return this.separators[index];
-    }
+    });
 
     export function emptyList<T extends ISyntaxNodeOrToken>(): T[] {
         return <T[]><any>_emptyList;
@@ -103,8 +110,8 @@ module TypeScript.Syntax {
             separators[i].parent = nodes;
         }
 
-
         nodes.separators = separators.length === 0 ? _emptySeparators : separators;
+        nodes.separatedListLength = nodes.length + separators.length;
 
         return nodes;
     }

src/services/syntax/syntaxWalker.generated.ts

@@ -28,7 +28,7 @@ module TypeScript {
         }
 
         public visitSeparatedList(list: ISyntaxNodeOrToken[]): void {
-            for (var i = 0, n = separatedListChildCount(list); i < n; i++) {
+            for (var i = 0, n = list.separatedListLength; i < n; i++) {
                 if (i % 2 === 0) {
                     list[i >> 1].accept(this);
                 }